FUEL SYSTEM
TABLE OF CONTENTS
page page
FUEL SYSTEM 2.5L TURBO DIESEL
DESCRIPTION............................1
WARNING...............................1
DIAGNOSIS AND TESTING..................1
AIR IN FUEL SYSTEM....................1
FUEL SUPPLY RESTRICTIONS.............1STANDARD PROCEDURE...................2
WATER DRAINING AT FUEL FILTER.........2
CLEANING FUEL SYSTEM PARTS...........2
SPECIFICATIONS.........................2
FUEL DELIVERY..........................3
FUEL INJECTION........................10
FUEL SYSTEM 2.5L TURBO
DIESEL
DESCRIPTION - DIESEL FUEL DELIVERY
SYSTEM
The fuel system on the 2.5L Common Rail Diesel
Engine uses a fuel injection pump and an Electronic
Control Module (ECM).
The fuel delivery system consists of the:
²Accelerator pedal
²Air cleaner housing/element
²Fuel filter/water separator
²Fuel heater
²Fuel heater relay
²Fuel transfer (lift) pump
²Fuel injection pump
²Fuel injectors
²Fuel tank
²Fuel tank filler/vent tube assembly
²Fuel tank filler tube cap
²Fuel tank module containing the rollover valve
and a fuel gauge sending unit (fuel level sensor).
²Fuel tubes/lines/hoses
²High-pressure fuel injector lines
²Low-pressure fuel supply lines
²Low-pressure fuel return line
²Overflow valve
²Quick-connect fittings
²Water draining
WARNING - HIGH FUEL SYSTEM PRESSURE
WARNING: THE INJECTION PUMP SUPPLIES HIGH-
PRESSURE FUEL TO EACH INDIVIDUAL INJECTOR
THROUGH HIGH-PRESSURE LINES. FUEL UNDER
THIS AMOUNT OF PRESSURE CAN PENETRATE
SKIN AND CAUSE PERSONAL INJURY. WEAR
SAFETY GOGGLES AND ADEQUATE PROTECTIVE
CLOTHING. AVOID CONTACT WITH FUEL SPRAY
WHEN BLEEDING HIGH-PRESSURE FUEL LINES.
DIAGNOSIS AND TESTING - AIR IN FUEL
SYSTEM
Air will enter the fuel system whenever fuel supply
lines, separator filters, injection pump, high-pressure
lines or injectors are removed or disconnected. Air
trapped in the fuel system can result in hard start-
ing, a rough running engine, engine misfire, low
power, excessive smoke and fuel knock. After service
is performed, air must be bled from the system
before starting the engine.
Inspect the fuel system from the fuel transfer
pump to the injectors for loose connections. Leaking
fuel is an indicator of loose connections or defective
seals. Air can also enter the fuel system between the
fuel tank and the transfer pump. Inspect the fuel
tank and fuel lines for damage that might allow air
into the system.
DIAGNOSIS AND TESTING - FUEL SUPPLY
RESTRICTIONS
LOW-PRESSURE LINES
Fuel supply line restrictions or a defective fuel
transfer pump can cause starting problems and pre-
vent engine from accelerating. The starting problems
include; low power and/or white fog like exhaust.
Test all fuel supply lines for restrictions or block-
age. Flush or replace as necessary. Bleed fuel system
of air once a fuel supply line has been replaced. Refer
to Air Bleed Procedure for procedures.
To test for fuel line restrictions, a vacuum restric-
tion test may be performed. Refer to Fuel Transfer
Pump Pressure Test.
HIGH-PRESSURE LINES
Restricted (kinked or bent) high-pressure lines can
cause starting problems, poor engine performance,
engine mis-fire and white smoke from exhaust.
Examine all high-pressure lines for any damage.
Each radius on each high-pressure line must be
smooth and free of any bends or kinks.
RGFUEL SYSTEM14a-1
Replace damaged, restricted or leaking high-pres-
sure fuel lines with correct replacement line.
CAUTION: High pressure lines cannot contact each
other or other components. Do not attempt to weld
high-pressure fuel lines or to repair lines that are
damaged. If line is kinked or bent, it must be
replaced. Use only recommended lines when
replacement of high-pressure fuel line is necessary.
STANDARD PROCEDURE - WATER DRAINING
AT FUEL FILTER
Refer to Fuel Filter/Water Separator removal/in-
stallation for procedures.
STANDARD PROCEDURE - CLEANING FUEL
SYSTEM PARTS
CAUTION: Cleanliness cannot be overemphasized
when handling or replacing diesel fuel system com-
ponents. This especially includes the fuel injectors,
high-pressure fuel lines, fuel rail, and fuel injection
pump. Very tight tolerances are used with these
parts. Dirt contamination could cause rapid part
wear and possible plugging of fuel injector nozzle
tip holes. This in turn could lead to possible engine
misfire. Always wash/clean any fuel system compo-
nent thoroughly before disassembly and then air
dry. Cap or cover any open part after disassembly.
Before assembly, examine each part for dirt, grease
or other contaminants and clean if necessary. When
installing new parts, lubricate them with clean
engine oil or clean diesel fuel only.
SPECIFICATIONS
SPECIFICATIONS - TORQUE
2.5L DIESEL - TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Crankshaft Position Sensor Bolt 10.8 8 96
Boost Pressure / Intake Air Temperature Sensor Bolts 5.4 Ð 48
Fuel Pump Nuts 27.5 21 Ð
Fuel Line Fittings at Pump 27.5 21 Ð
Fuel Pump Sprocket Nut 88.3 65 Ð
Fuel Injector Retaining Bolts 32.4 24 Ð
High Pressure Fuel Lines 22 17 194
Fuel Rail Bolts 27.5 21 Ð
14a - 2 FUEL SYSTEMRG
FUEL SYSTEM 2.5L TURBO DIESEL (Continued)
FUEL DELIVERY
TABLE OF CONTENTS
page page
FUEL RAIL
DESCRIPTION............................3
OPERATION.............................3
REMOVAL...............................3
INSTALLATION............................4
FUEL FILTER / WATER SEPARATOR
DESCRIPTION............................4
OPERATION.............................4
FUEL LINES
DESCRIPTION............................5
OPERATION.............................5
DIAGNOSIS AND TESTING..................5HIGH-PRESSURE FUEL LINE LEAKS........5
FUEL TRANSFER PUMP
DESCRIPTION............................6
OPERATION.............................6
FUEL INJECTION PUMP
DESCRIPTION............................6
REMOVAL...............................6
INSTALLATION............................8
WATER IN FUEL SENSOR
DESCRIPTION............................9
OPERATION.............................9
FUEL RAIL
DESCRIPTION
The fuel rail is mounted to the cylinder head cover/
intake manifold. (Fig 1).
OPERATION
The fuel rail stores the fuel for the injectors at
high pressure. At the same time, the pressure oscil-
lations which are generated due to the high-pressure
pump delivery and the injection of fuel are dampened
by the rail volume.
The fuel rail is common to all cylinders, hence it's
name ªcommon railº. Even when large quantities of
fuel are extracted, the fuel rail maintains a constant
inner pressure. This ensures that the injection pres-
sure remains constant from the moment the injector
opens.
REMOVAL - FUEL RAIL
(1) Disconnect negative battery cable.
(2) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(3) Disconnect fuel injector high pressure lines.
(4) Disconnect fuel rail supply line. (Fig. 2)
(5) Disconnect fuel rail return line. (Fig. 2)
(6) Disconnect fuel rail high pressure sensor con-
nector. (Fig. 2)
(7) Remove engine electrical harness retainers
from the fuel rail retaining bolts/studs. (Fig. 2)
(8) Remove fuel rail retaining bolts and remove
fuel rail (Fig. 2).Fig. 1 ENGINE COMPONENT LOCATIONS
1 - FUEL INJECTOR RETURN LINE
2 - FUEL INJECTOR SUPPLY LINE
3 - OIL SEPARATOR
4 - FUEL INJECTOR
5 - CAMSHAFT POSITION SENSOR
6 - BOOST PRESSURE/INTAKE AIR TEMPERATURE SENSOR
7 - EGR SOLENOID
8 - FUEL PRESSURE SENSOR
9 - CYLINDER HEAD COVER/INTAKE MANIFOLD
10 - FUEL RAIL
11 - WIRING HARNESS RETAINING CLIPS
RGFUEL DELIVERY14a-3
INSTALLATION - FUEL RAIL
(1) Install fuel rail to intake manifold/cylinder
head cover (Fig. 2). Torque retaining bolts to
27.5N´m.
(2) Install engine electrical harness retainers from
the fuel rail retaining bolts/studs. (Fig. 2)
(3) Connect fuel rail high pressure sensor electri-
cal connector. (Fig. 2)
(4) Connect fuel rail return line. (Fig. 2)
(5) Connect fuel rail supply line. (Fig. 2)
(6) Connect fuel injector high pressure lines. (Fig.
2)
(7) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION) .
(8) Connect negative battery cable.
FUEL FILTER / WATER
SEPARATOR
DESCRIPTION
The fuel filter/water separator assembly is located
under the vehicle in front of the rear axle assembly
(Fig. 3). The assembly also includes the fuel heater
and Water-In-Fuel (WIF) sensor.
OPERATION
The fuel filter/water separator protects the fuel
injection pump by removing water and contaminants
from the fuel. The construction of the filter/separator
allows fuel to pass through it, but helps prevent
moisture (water) from doing so. Moisture collects at
the bottom of the canister.
Fig. 2 FUEL RAIL COMPONENTS
1 - FUEL INJECTOR RETURN LINE
2 - FUEL INJECTOR SUPPLY LINE
3 - OIL SEPARATOR
4 - FUEL INJECTOR
5 - CAMSHAFT POSITION SENSOR
6 - BOOST PRESSURE/INTAKE AIR TEMPERATURE SENSOR
7 - EGR SOLENOID
8 - FUEL PRESSURE SENSOR
9 - CYLINDER HEAD COVER/INTAKE MANIFOLD
10 - FUEL RAIL
11 - WIRING HARNESS RETAINING CLIPS
Fig. 3 FUEL FILTER/WATER SEPARATOR
1 - LIFT PUMP RETAINING BOLTS
2 - LIFT PUMP
3 - FUEL FILTER/WATER SEPARATOR HOUSING
4 - FUEL HEATER
5 - CHECK BALL
6 - O-RING
7 - FLOW DIVERTER
8 - FUEL FILTER
9 - O-RING
10 - FUEL FILTER BOWL ASSEMBLY
14a - 4 FUEL DELIVERYRG
FUEL RAIL (Continued)
Refer to the maintenance schedules for the recom-
mended fuel filter replacement intervals.
For draining of water from canister, refer to Fuel
Filter/Water Separator Removal/Installation section.
A Water-In-Fuel (WIF) sensor is part of the fuel fil-
ter cap. Refer to Water-In-Fuel Sensor Description/
Operation.
The fuel heater is installed into the filter/separator
housing above the fuel filter. Refer to Fuel Heater
Description/Operation.
FUEL LINES
DESCRIPTION
All fuel lines up to the fuel injection pump are con-
sidered low-pressure. This includes the fuel lines
from: the fuel tank to the fuel transfer pump, and
the fuel transfer pump to the fuel injection pump.
The fuel return lines and the fuel drain lines are also
considered low-pressure lines. High-pressure lines
are used between the fuel injection pump and the
fuel injectors. Also refer to High-Pressure Fuel Lines
Description/Operation.
DESCRIPTIONÐHIGH PRESSURE FUEL LINES
The high-pressure fuel lines are the 4 lines located
between the fuel injection pump and the fuel injec-
torsctor tubes. All other fuel lines are considered low-
pressure lines.
OPERATIONÐHIGH PRESSURE FUEL LINES
CAUTION: The high-pressure fuel lines cannot con-
tact each other or other components. Do not
attempt to weld high-pressure fuel lines or to repair
lines that are damaged. If lines are ever kinked or
bent, they must be replaced. Use only the recom-
mended lines when replacement of high-pressure
fuel line is necessary.
High-pressure fuel lines deliver fuel under
extremely high pressure from the injection pump to
the fuel injectors. The lines expand and contract from
the high-pressure fuel pulses generated during the
injection process. All high-pressure fuel lines are of
the same length and inside diameter. Correct high-
pressure fuel line usage and installation is critical to
smooth engine operation.
WARNING: USE EXTREME CAUTION WHEN
INSPECTING FOR HIGH-PRESSURE FUEL LEAKS.
INSPECT FOR HIGH-PRESSURE FUEL LEAKS WITH
A SHEET OF CARDBOARD. HIGH FUEL INJECTION
PRESSURE CAN CAUSE PERSONAL INJURY IF
CONTACT IS MADE WITH THE SKIN.
DIAGNOSIS AND TESTING - HIGH-PRESSURE
FUEL LINE LEAKS
High-pressure fuel line leaks can cause starting
problems and poor engine performance.
WARNING: DUE TO EXTREME FUEL PRESSURES,
USE EXTREME CAUTION WHEN INSPECTING FOR
HIGH-PRESSURE FUEL LEAKS. DO NOT GET YOUR
HAND NEAR A SUSPECTED LEAK. INSPECT FOR
HIGH-PRESSURE FUEL LEAKS WITH A SHEET OF
CARDBOARD. HIGH FUEL INJECTION PRESSURE
CAN CAUSE PERSONAL INJURY IF CONTACT IS
MADE WITH THE SKIN.
Start the engine. Move the cardboard over the
high-pressure fuel lines and check for fuel spray onto
the cardboard (Fig. 4). If a high-pressure line connec-
tion is leaking, bleed the system and tighten the con-
nection. Refer to the Air Bleed Procedure in this
group for procedures. Replace damaged, restricted or
leaking high-pressure fuel lines with the correct
replacement line.
CAUTION: The high-pressure fuel lines cannot con-
tact each other or other components. Do not
attempt to weld high-pressure fuel lines or to repair
lines that are damaged. Only use the recommended
lines when replacement of high-pressure fuel line is
necessary.
Fig. 4 Typical Test for Leaks with Cardboard
1 - HIGH-PRESSURE LINE
2 - CARDBOARD
3 - FITTING
RGFUEL DELIVERY14a-5
FUEL FILTER / WATER SEPARATOR (Continued)
(12) Install accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(13) Install power steering belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(14) Install air cleaner housing assembly.
(15) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION).
(16) Connect negative battery cable.
WATER IN FUEL SENSOR
DESCRIPTION
The WIF sensor is located in the bowl assembly of
the fuel filter/water separator.
OPERATION
The sensor sends an input to the Engine Control
Module (ECM) when it senses water in the fuel filter/
water separator. As the water level in the filter/sep-
arator increases, the resistance across the WIF
sensor decreases. This decrease in resistance is sent
as a signal to the ECM and compared to a high
water standard value. Once the value reaches 30 to
40 kilohms, the ECM will activate the water-in-fuel
warning lamp through CCD bus circuits. This all
takes place when the ignition key is initially put in
the ON position. The ECM continues to monitor the
input at the end of the intake manifold air heater
post-heat cycle.
RGFUEL DELIVERY14a-9
FUEL INJECTION PUMP (Continued)
FUEL INJECTION
TABLE OF CONTENTS
page page
FUEL INJECTOR
DESCRIPTION...........................10
OPERATION.............................10
REMOVAL..............................11
INSTALLATION...........................12
ACCELERATOR PEDAL POSITION SENSOR
DESCRIPTION...........................12
OPERATION.............................12
REMOVAL..............................12
INSTALLATION...........................13
BOOST PRESSURE SENSOR
DESCRIPTION...........................13
OPERATION.............................13
DIAGNOSIS AND TESTING.................13BOOST PRESSURE SENSOR.............13
INTAKE AIR TEMPERATURE SENSOR
DESCRIPTION...........................13
OPERATION.............................13
REMOVAL..............................13
INSTALLATION...........................14
CRANKSHAFT POSITION SENSOR
DESCRIPTION...........................14
OPERATION.............................14
MASS AIR FLOW (MAF) SENSOR
DESCRIPTION...........................14
OPERATION.............................15
REMOVAL..............................15
INSTALLATION...........................15
FUEL INJECTOR
FUEL INJECTOR
There are individual fuel injectors for all four cyl-
inders. These fuel injectors are used to spray fuel
into the combustion chamber (Fig. 1).
OPERATION
The injector operation can be subdivided into four
operating states with the engine running and the
high-pressure pump generating pressure:
²Injector closed (with high pressure applied)
²Injector opens (start of injection)
²Injector opened fully
²Injector closes (end of injection)
Injector closed (with high pressure applied)
With the injector closed (at-rest state), the solenoid
valve is not energized and is therefore closed. With
the bleed orifice closed, the valve spring forces the
armature's ball onto the bleed-orifice seat. The rail's
high pressure build up in the valve control chamber,
and the same pressure is also present in the nozzle's
chamber volume. The rail pressure applied at the
control plunger's end face, together with the force of
the nozzle spring, maintain the nozzle in the closed
position against the opening forces applied to its
pressure stage (Fig. 2).
Fig. 1 FUEL INJECTOR
1 - FUEL INJECTOR
2 - NOZZLE
3 - FUEL INLET FITTING
4 - ELECTRICAL CONNECTION
14a - 10 FUEL INJECTIONRG
INSTALLATION
NOTE: Be sure the copper washer is installed on
end of injector before installing in cylinder head.
(1) Install fuel injector in cylinder head.
(2) Install fuel injector retainer and bolt (Fig. 3).
Torque bolt to 32.4 N´m.
(3) Install fuel injector high pressure line (Fig. 3).(4) Install fuel return line to injector (Fig. 3).
(5) Connect fuel injector electrical connector.
(6) Install engine cover (Refer to 9 - ENGINE
COVER - INSTALLATION).
(7) Connect negative battery cable.
ACCELERATOR PEDAL
POSITION SENSOR
DESCRIPTION
The accelerator pedal position sensor mounts to
the accelerator pedal bracket (Fig. 4).
OPERATION
The accelerator pedal position sensor contains a
potentiometer that is operated by the accelerator
pedal. As the accelerator pedal is depressed and
released, the sensor provides a variable voltage sig-
nal to the engine control module. This voltage signal
is directly proportional to accelerator pedal position.
When the pedal is fully depressed, the voltage signal
is high.
REMOVAL - PEDAL POSITION SENSOR (LHD)
(1) Disconnect negative battery cable.
(2) Disconnect pedal position sensor electrical con-
nector (Fig. 4).
Fig. 3 FUEL SYSTEM COMPONENTS
1 - FUEL RAIL RETAINING BOLT
2 - FUEL RAIL RETAINING STUD
3 - FUEL RAIL RETURN LINE
4 - FUEL RAIL
5 - FUEL RAIL SUPPLY LINE
6 - IDLER PULLEY
7 - CRANKSHAFT PULLEY
8 - CRANKSHAFT PULLEY RETAINING BOLTS
9 - BELT TENSIONER RETAINING BOLT
10 - BELT TENSIONER
11 - FUEL INJECTOR RETAINER
12 - FUEL INJECTOR RETURN LINE
13 - FUEL INJECTOR RETAINING BOLT
14 - FUEL INJECTORS
15 - FUEL INJECTOR HIGH PRESSURE SUPPLY LINESFig. 4 ACCELERATOR PEDAL POSITION SENSOR
LOCATION (TYPICAL)
1 - ACCELERATOR PEDAL POSITION SENSOR ELECTRICAL
CONNECTOR
2 - ACCELERATOR PEDAL POSITION SENSOR
3 - ACCELERATOR PEDAL
4 - ACCELERATOR PEDAL MOUNTING BRACKET
14a - 12 FUEL INJECTIONRG
FUEL INJECTOR (Continued)